Automatically adjustable vehicular brake



I March 2s, 1944.

E. J. NAcHTwEY 2,345,062 AUTOMATICALLY ADJusTABLE vEmcULAR BRAKE Filed March 26, 1941 3 Sheets-Sheet 1 XZ ZO l ,Zz y ,0 5 29 ,i a G26 fe ffy; 24 d 89 v I i 8\ 37 7`7 54 5 K5 y 8' 56 66 v( /f a7 5 555m 9 7o O @a l/l/ j s O K7, 92 'T88 68 l 'lr6 66 6 66u67 o l, :1,4 /8 9, l y; ,6 lah ilk 'I o P0 l /41'1' 1 i 91 99 97 ,f/ 296 o 98. Y, .moo 96 if l 95 fox 05 )8 U 9 v9 8l 56 94 /5 v 8 r de. l `-s` 85 Qi f l5 f 96 )6 9K j? EPWAKD NACHTWEK March 28, 1944. E, J, NACHTWEY 2,345,062

-AUTOMATICALLY ADJUSTABLE VEHICULAR BRAKE Filed March 26, 1941 5 Sheets-Sheet 2 Epw/sgp J. NACHTWEY.

ma 70m March 28, 1944. E. J. NAcHTwEY 2,345,052

ATOMATICALLY ADJUSTABLE VEHICULAR BRAKE Filed March 26, 1941 3 Sheets-Sheetw EDWA QD I NAcHTwEY.

m Mmmww Patented Mar. 28, 1944 UNITED STATE s PAT-ENT4 or Fics AUTOMATICALLY ADJUSTABLE VEHIiILAIIt BRAKE 12 Claims.

The present invention concerns. improvementsin hydraulic brakes and has for one of its objects the combination of the .best features of both hydraulic and mechanical brakes in a single brake.

It is an object of the invention to provide a novel adjuster' which maintains the lining at a predetermined distance from the drum at all times whereby even wear on the lining is obtained and the brake pedal movement for a given braking action is substantially constant.

vIt is an object of the invention to provide means for arresting and temporarily discontinuing the action of the adjuster when the drum is expanded abnormally due to heat.

It is an object of the invention to provide novel means for lengthening the shoe of the brake as wear may require.

It is an object of the invention to float support the shoe.

It is an object. of the invention to provide mechanical means for operating the brake should the hydraulic means fail, said mechanical means being of independent action, but operated by the same pedal.

It is an object of the invention to provide novel pedal connecting means whereby a proper sequence of 4actions is determined.

Reference is had to my previous brake patents, No. 2,186,264, issued January 9, 1940, and No. 2,132,576, issued August 8, 1936, for closely related disclosures which will aid in fully understanding the present device.

Other objects will readily appear upon careful consideration of the drawings and specification which are to be taken as illustrative of one form the invention may take and are not to be construed as limiting.

n In the drawings:

Figure 1 is a plan view partially sectional and partially broken away of the brake assembly.

Figure 2 is a section detail of the shoe lengthening mechanism.

Figure 3 is a fragmentary oblique elevation o f an adjuster assembly shown in section along line 3--3 in Figure l.

Figure 4 is a horizontal sectional view taken on section line 4 of Fig. 3, showing one form of adjuster wedge arrangement.

Figure 5 is a View similar to Fig. 4 of another form of adjuster wedge arrangement.

Figure 6 is an elevation of a spring supportv detail.

Figure 7 is a fragmentary sectional view along line 'I-'I of Figure 1 showing mounting detail,

Figure 8 is a fragmentary, elevation of -the' pedal arrangement showing the ,novel pedal 'connection means. Y

Figure 9 is a section'cletail along line 9--9 of l Figurel. y .l In the drawings likenumerals refer to like. parts throughout. y A brake drum Iii is mounted on and turns with a wheel rotatably mounted on axle II. A base plate I2 mates with drum Ill as at I3 where a reasonably effective dirt seal is provided withv due allowance for running clearance.

Housed within drum Iii base plate I2 are shoes I4, one on each side, and a third shoe I5 at the bottom. The outer curved faces of all three shoes are provided with well known lining material It adapted to frictionally engage the inner surface of drum III. A suitable. running clearance I'I is provided between lining I6 and theinner surface of drum Ill. It is this clearancek il which the present invention maintains lat a practicalv constant throughout the life of lining I6.

Shoes I4 have an inwardly extending webbingA or flange portion I8. Shoe I5 is provided with a similar webbing or flange portion IS. Webbings I8 and I9 form,T-shaped sections'with` their respective shoesv whichA are strengthened thereby. In addition the webbings VIS and I9 serve as movable mounting means for certain` portions of the invention. j,

An hydraulic cylinder 2t is rmly mounted .on the upper part of base plate I2 between the upper ends of shoes It by `carriage or blocks means 2I, which maybe bolted or otherwise fastenedI to base plate I2. A piston or plungermeans 22 closes each end of cylinder 20 and slides therein. Within thecylinder is a compression spring 23 which bears on pillow blocks 24 also within cylinder 20 and resting against pistons 22.

A tension spring 25 draws together the `upper ends of shoes I4.' Springs 23 and'25 cooperate to eliminate loose play between the pistons 22 and shoes I4. The outer end of each piston 22 terminates in bifurcations 25 between which is mounted depending armlby means of a pin 28. An elongate slot 29 is provided in bifurcations 26 to allow relative movement of arm 21 with respect thereto. The upper ends of shoes I4 extend between bifurcations 2G 'and contact the upper or head endsof arms 2i.

Just below spring 25 is a lever Sil pivoted in mountings 3| attached to base plate I2 and extending through slot 32 therein.

The base or transverse portion 33 of lever 3l) is internally threaded as at 3ft to yield a cam action on threaded portions 35 of members 36 which are recessed at 31 to receive the lower portions of depending arms 21. Recesses 31 are elongate and may be open at the ends, arms 21 normally resting against the inner walls of the recesses. Threaded portions 34 and 35 are so arranged that clockwise or downward rotation of lever 36 will cause members 36 to move apart.

A conduit 38 connects cylinder 26 with master cylinder 39 in a fluid tight system. Brake pedal 40 is pivoted at 4| and is provided with a rearwardly projecting lug 42 to which is pivoted rod 43 leading to cylinder 39. Rod 43 may be con- Yed toward the center of base plate I2. Within each housing are two wedge members 16 and 1I nected with a reciprocating piston within cylinvder 39 or one wall of the cylinder may be ilexible as shown at 44. Clockwise rotation of Vpedal 46 about pivot 4I will be seen to raise rod 43 and force fluid from master cylinder 39 through conin the'right and left-hand housings.

duits 38 to the cylinders 26 in each of the wheels.

A counterclockwise tension return spring may be provided for pedals 46 if desired.

On lever portion 45 of pedal 46 and adjacent the pivot 4I is provided a projecting lug or the like `46 with a flat surface extending approximately radially from pivot 4I. A second pivoted member 41 is likewise pivoted at 4| and has projecting therefrom a lug or the like 48 extending approximately radially from pivot 4I and having a flat upper surface adapted to be engaged by the similar flat surface on lug 46. Member 41 has downwardly and upwardly projecting lugs 49 and 56 attached thereto. Lug 56 has a relatively slenderer portion 5| which extends farther from pivot 4I than does lug 49 and has van apertured projection 52 mounted adjacent one edge thereof. Tension rod 53 slides freely through projection 52 until stop 54 mounted on its end engages projection 52. Rod 53 is pivoted' at its other end to lever 65 which will serve as an emergency or parking brake lever.

Cables 55 are pivoted to lugs 49 and 56 of member 41. One cable 55 leads to the rear wheels and the other to the front pair. The usual lever type of equalizing device, not shown, may be employed between the wheels of each pair. Cables 55 are well graphited and lead through pipes 56 which are held in place by standards 51. Cable 55 leads over around pulley 58 pivoted on trun nion 59 mounted on axle 66. Portion 6I of cable 55 ends in a loop 62 which rests in depression 63 of lever 36.

It will be noted that the center line of cable 55 where it leaves the pulley 58 and extends toward lever 36 lies on the axis or center line of king pin 64 which arrangement permits the free turning of the Wheel without affecting the, tension in cable 55 or its braking action. The center of depression 63 need not depart from the axis of king pin 64 a greater distance than the radius of cable 55. If desired a sprocket maybe substituted for pulley 58 and a chain for portion 6I of cable 55.

As the lining I6 wears the running clearance I1 would increase requiring increased movement of pedal 40 or lever 65 for adequate braking. Of greater importance is the tendency of linings to wear unevenly and the clearance I1 tending'to become greater at some spots than others.

This defect is corrected by my adjuster which ',"sldable on the bottom, against the converging sides thereof and against each other. The same forms of wedges 16 and 1I are used in either form of housing, but they are placed reverse side up A bifurcated spring 12 is pivoted at 13 in the curved outer wall of each housing and urges both wedges 1i6and 1| toward the converging portion of each. The relationship of the wedges 10 and 1I is such that as wedge 16 is moved away from the point of convergence wedge 1I is moved toward it under the shoe.

the action of bifurcated spring 12 and the return of wedge 16 is prevented. Wedge 16 has a hole 14 therethrough substantially at its center of gravity in which is mounted bolt member 15 which may be driven or threaded into place. Bolt member 15 extends through a hole`16 in the top of housing 66 at which point it has an enlarged portion 11. Hole 16 is of suflicient size to allow free movement of bolt member 15 toward drum I6.

,A cover plate 18 ts snugly around bolt 15 and over hole 16 in sliding relation with the top of housing 66 to exclude dirt and the like.

' Around the top of bolt 15 is a rectangular member 19 which rests on enlarged portion 11, bears against webbing I8 and slides on cover plate 18. Member 19 may be held in place by a nut or the like as shown. A lever arm 8| is pivoted at 86 to webbing I8 and has an extension 82 which curves around adjacent to the side of member 19 removed from webbing I8. The end 83 of extension 82 is spaced from the member 19 a distance substantially equivalent to clearance I1 as is shown in Fig. 3. A second extension 84 projects from the body of lever 8| and is held rmly against plate 55 by spring 86. Plate 85 is mounted on thermostatic bellows member 81 which is connected by a suitable conduit to heat absorber 68' containing a quantity of ether or material having similar desirable thermo-physical properties. Thermostatic bellows member 81 is held in place byv ring 89 welded or otherwise attached to shoe I4. Absorber 88 rests snugly against shoe I4 in intimate heat exchange relation therewith and extends around nearly the entire length of Each shoe normally has its own absorber 'and each adjuster has its own bellows member.

Lower shoe I5 is supported resiliently by springs 96 anchored at 9| to base plate I2. Housings 92 are located each end of shoe I5 and are provided with upstanding ears 93 to which one end of each oi springs 96 is attached. Fitted within housings 92Y are wedges 94 and 95 which rest against each other and the walls of housing 92 in sliding relation. Wedges 94 are pivoted at 96 to the lower ends of each of shoes I4. Wedges 95 are likewise connected to pivot 96 by levers 91 and links 98.

Tension spring 99 has one end attached to the central portion of one lever 91 and the other to the'other lever 91. A bridle |66 may be used to in form as shown in Figs. 4 and 5 and are desiggive clearance if desired or a direct connection tion through'mounting |93, Figs. l and 6.

ease with which portionvl92 slides.

In operation should it be desired to apply the brakes, pedal 49 is depressed, but not sufficiently to cause projection 46 to contact projection 48.`

Lug 42 raises rod 43` and forces iiuid through conduit 38 to cylinder 20 separating pistons 22.v Pistons 22 force the upper ends of shoes I4 apart. against the action of spring 25. Shoes I4 movef' outward, pivoting outward at 83 and shoe I5 is.

self energizing braking action with a gradualv increase in contact and force.

As the shoes I4 and I5 move outwardly to contact drum I9 webs I8 and I9 and the lever arms 8I pivoted thereon are carried along. Web I8 and the outer side of member 19 separate until the space between end 83 of extension 82 and the face of member 19 is taken up. This space is equal to clearance I1 and at the time of contact of 83 and 19, lining I6 is experiencing braking action against drum I9. As lining I6 experiences wear and becomes thinner, web I8 and lever 82 move closer to drum I9 by the amount of said wear. Since extension 82 and member 19 were in contact, member 19 is likewise moved toward the drum a distance equal to the amount of such wear. In this manner the distance between web I8 and member 19 is maintained equal to original clearance I1 during braking action. It is to be noted that the advance of member 19 takes place continuously as the wear occurs and not in steps. In this respect the adjuster is an improvement over my previous patents. Member 19 carries wedge 19 along with it through the action of bolt 15, the same being true of cover plate 18. As wedge 19 is moved toward drum I9 spring 12 moves wedge 1I away from drum I9. Wedges 10 and 1I experience relative sliding action and the action of wedge 1I effectively prevents any return of wedge 19. It will be seen that when the pedal 49 is released shoes I4 and I5 may move away from drum I9 a distance equal to original clearance I1 regardless of the amount of wear experienced by linings I6 since farther movement is prevented by member 19 which has advanced toward drum I9 by the amount of such wear. Thus the amount of movement of pedal 49 required for a given braking action is the same throughout the life of the lining I6.

During warm weather or because of much braking or both the temperature of drum I9 is Afrequently raised several hundreds of degrees. The resultant expansion of drum I9 which is of metal causes its inner surface to move away from lining I9 a distance substantially greater than clearance I1 which normally is about l@ of an inch. Such expansion causes a false adjusting action by members 19, 19 and 82 which results in such a reduction of clearance I1 as to cause the linings I6 to drag on drum I9 or to lock and prevent rotation of the wheel entirely. This last is most inconvenient and expensive. Should it occur while the vehicle is in motion it is of course most dangerous.

Accordingly lever 8I ls provided with a second extension 84 bearing on plate 85 on thermostatic bellows 81. Bellows 81 is connected with an absorber 88 lled with ether or other fluid having satisfactory characteristics. Tube or absorber 88 is preferably placed on the inner side close to back plate I2 and as near drum I9 as possible. Itlshould be protected from flying particles and the like.

When the temperature ofdrum I9 is such that over or false correction would occur the iluid in absorber 88 either by expansion of fluid or by turning into a gas causes bellows 81 to expand.'

The expansion of bellows 81 moves extension 84 awayV fromdrum I9 and rocks it about pivot 89. This action moves extension 82 away from member 19 and interrupts adjusting action while the drum I9 is overheated. Wheny drum I9 cools the uid in absorber 88 likewise cools and extension 82 and member 19 are restored to their former relationship.

Aslining I9 wears the effective diameter of the shoe assembly must be maintained. This is accomplished by the action of wedges 94 and 95 in housings 92. When the wearing of lining I9 causes member 19 to move outward it likewise causes wedges 94 to move out of housing 92. Simultaneously wedge 95 is forced inwardly under the action of spring 99 to take its place. Wedge 95 effectively prevents the return of wedge 94 and the combined action of springs 99 and 99 maintains the assembly in position.

Where clearance I1 is Mg of an inch the movement of pistons 22 may be taken as 21rAR or e inch. Where the master cylinder 39 has the same diameter as cylinders 29 the total movement oi rod 43 need not be much more than inch to take care of all four brakes. A clearance of 31a inch would require only 3A of an inch movement.

If for any reason the hydraulic system fails to` spring or like means is used to return pedal 49.'

v Member 41 may also be actuated by emergency or parking lever 95 which acts through rod 53 slidably fastened at 52 on extension 5I of member 41.

It will be noted that cylinder 29 serves as an anchor for the shoes I4. Pistons 22 rest on the rounded shoulders at the ends of cylinder 29. In this position all adjustment stops. This rounded shoulder bears and centers the initial thrust due to the braking action. Depending upon the direction of rotation one end or the other of the cylinder 29 is utilized.

It will be seen that there are two distinct adjusting operations. First, when the brakes are applied adjuster elements 1I), 19 are drawn out as needed to correct for the wear of linings I6. While the brakes are thus expanded the adjustment of wedge members 94, 95 for length cannot occur since the braking action forces these wedge members firmly together.

Upon the release of pedal 49 springs 99 lift shoe I5 through web I9 away from drum I9 until it rests against adjuster block or member 19. Spring 25 performs a like function for shoes I4. This action of spring 25 withdraws wedge 94 vanced .toward drum I 0,1; correct for Wear ci lining IE. Relative movement of wedge member 94 and 95 continues until pistons 22 reston the rounded shoulders at the ends of cylinderV 20.

Spring 25 must be strong enough to accomplish.V

this action and cause rm seating ofthe pistons in the cylinder. Y drum I0 and linings IB is thereby assured, Spring 25 thus has the triple function of eliminating.

loose play, releasing the brakes and causing the adjustment for length by 'drawing the upper shoes I4 out of housing 92 in shoes I5 Where linings I6 wear and the shoes fill and l5be`come too short to return thepistons'22 to normal position against the shoulders of cylinder 20.

I claim:

l. In a vehicular brake, a drum, av shoe mou'ntfl ed in close proximity thereto, `adjusting means'A operatively connected to said shoe, a portionof said adjusting means being. movable with said shoe upon the occurrence of wear, means connected to said shoe formcving it; toward saiddrum, a second portion of `said adjusting means being wedge shaped and constructed to positively hold said rst portion `in an `advanced position,l

thermally controlled means associated with said adjusting means and arranged to arrest its motion whereby adjustment is interrupted during periods' of substantial drum expansion due to temperature rise.

2. In a vehicular brake, a drum, a shoe mounted adjacent said drum with a certain running clearance therebetween, adjusting means oper-y atively connected to said shoe, a fportion of said adjustingfmeans being movable with said shoe` upon the occurrence of wear, brake applying means connected to said shoe, a second portion of said adjusting means being wedge shaped and arranged to positively hold said rst portionvin an V advanced position, said adjusting means being so constructed that said shoe may be moved away from said drumby the amount of said clearance and there heldycontrollingmeans associated with said adjusting means and arranged to interrupt` the operation thereof whereby adjustmentis in,V

terrupted during periods of substantial drum exlpansion or shoe shrinkage from whatever cause.

3. The combination` set forth in claim 2, saidcontrolling means constructed to engage said adjusting means and move it out of adjusting position during periods when saidclearance is great-A er than normal due to causes other than wear of said shoe.

4. The combination set forth in lclaim 2, said: controlling means comprising anelon'gated thermally sensitive chamber disposed along said shoe.

' gfThe combination set forth in claim 2said said clearance exceed a certain amount.

Proper clearance between the against and move said movable portion should:

slightly from housing 92 if wedge III has been ad.-

6. In a vehicular brake, a drum, a plurality of shoes, means connect-ed to said shoescomprising mating wedges in a Wedge shaped housingwhereby their combined effective length may be in- ,7., In a vehicular4 brake, a drum, a plurality of shoes, intertting wedge shaped members in a wedge shaped housing connecting said shoes in a slidable manner whereby the combined eifective lengthof said shoes may be increased to allow for wear, said Vwedge. shaped housing being construc-ted and cooperating with said wedge shaped members so nicely thatl an adjustment advance howeverxsmall Lis firmly held without slip.

8.V The combination setforth in claim-.7, said interfltting wedge shaped 1 members providing locking action against the walls of said housing whereby said sliding is unidirectional and resilientmeans .urging one of. said wedge-shaped members into said housing. l

9. In combination, an adjusting means for a vehicular brake comprising a brake shoe, a base member, a wedge' shaped movable memberA mounted onsad basamember, v,locking means positively limitingany unwanted movement of said movable member,` brake shoe contact means mounted on said movable member, a pivoted contact arm. mounted on said brake shoe and arrangednto engage and. movesaid contact meansv to eiect adjustment, said-contact arm being movi able into and out of engaging relation with said contact means. v i

10.In combination, lanadjusting means for a vehicular brake, having a drum anda shoe, comprising a base member, a movable member mounted on.l saidl base member, unidirectional lockingmeans Vadjacent rsaid movable :member and limiting on1y,the return movement thereof, contact means mounted on said movable member, a pivotedicontact arm mounted on said shoe and arranged tok Contact and move said contact meansto eiect adjustment, a normal clearance between said uarm and said contact means, substantiallyequal to the-normal clearance between said shoe and said drum. f

11. The combination senforth in daim 10, said contact arm being movable into and out of contact relation with said contact means, a projec-cl tion on said contact arm, thermally -responsive means mounted adjacent saidY contact arm and` on said shoes having interfittingwedge shaped parts onfadjacentshoe portions whereby an effe'ctive total length of said shoes may be maintained. 

